UPDATE: Tryied the apache configuration proposed but it still not working.

I was able to obtain the token using ruby oauth client, still not working via PHP

oauth \
  --verbose \
   --query-string \
   --consumer-key 3157bsm22p5q80t7zcujfi9uzxafefic \
   --consumer-secret zo22y43t1d63okihubfgkg39rdg3pjvl \
   --access-token-url http://magento.host/oauth/token \
   --authorize-url http://magento.host/oauth/authorize \
   --request-token-url http://magento.host/oauth/initiate \
   authorize

    <?php
 

class Vashi_Restapi_TestController extends Mage_Core_Controller_Front_Action {

    public function indexAction() {

        //Basic parameters that need to be provided for oAuth authentication
        //on Magento
        $params = array(
            'siteUrl' => Mage::getBaseUrl().'/oauth',
            'requestTokenUrl' => Mage::getBaseUrl().'/initiate',
            'accessTokenUrl' => Mage::getBaseUrl().'/oauth/token',

            'consumerKey' => '3157bsm22p5q80t7zcujfi9uzxafefic',//Consumer key registered in server administration
            'consumerSecret' => 'zo22y43t1d63okihubfgkg39rdg3pjvl',//Consumer secret registered in server administration
            'callbackUrl' => Mage::getBaseUrl().'/restapi/test/callback',//Url of callback action below
        );

        // Initiate oAuth consumer with above parameters
        $consumer = new Zend_Oauth_Consumer($params);
        // Get request token
        $requestToken = $consumer->getRequestToken();

        // Get session
        $session = Mage::getSingleton('core/session');
        // Save serialized request token object in session for later use
        $session->setRequestToken(serialize($requestToken));
        // Redirect to authorize URL
        $consumer->redirect();

        return;
    }

    public function callbackAction() {

        //oAuth parameters
        $params = array(
            'siteUrl' => Mage::getBaseUrl().'/oauth',
            'requestTokenUrl' => Mage::getBaseUrl().'/initiate',
            'accessTokenUrl' => Mage::getBaseUrl().'/oauth/token',
            'consumerKey' => '3157bsm22p5q80t7zcujfi9uzxafefic',
            'consumerSecret' => 'zo22y43t1d63okihubfgkg39rdg3pjvl'
        );

        // Get session
        $session = Mage::getSingleton('core/session');
        // Read and unserialize request token from session
        $requestToken = unserialize($session->getRequestToken());
        // Initiate oAuth consumer
        $consumer = new Zend_Oauth_Consumer($params);
        // Using oAuth parameters and request Token we got, get access token
        $acessToken = $consumer->getAccessToken($_GET, $requestToken);
        // Get HTTP client from access token object
        $restClient = $acessToken->getHttpClient($params);
        // Set REST resource URL
        $restClient->setUri(Mage::getBaseUrl().'/api/rest/products');
        // In Magento it is neccesary to set json or xml headers in order to work
        $restClient->setHeaders('Accept', 'application/json');
        // Get method
        $restClient->setMethod(Zend_Http_Client::GET);
        //Make REST request
        $response = $restClient->request();
        // Here we can see that response body contains json list of products
        Zend_Debug::dump($response);

        return;
    }
}

<?php

  class Vashi_Restapi_TestController extends Mage_Core_Controller_Front_Action {

    public function indexAction() {

    //Basic parameters that need to be provided for oAuth authentication
    //on Magento 

         $params = array(
            'siteUrl' => Mage::getBaseUrl().'/oauth',
            'requestTokenUrl' => Mage::getBaseUrl().'/initiate',
            'accessTokenUrl' => Mage::getBaseUrl().'/oauth/token',

            'consumerKey' => '3157bsm22p5q80t7zcujfi9uzxafefic',//Consumer key registered in server administration
            'consumerSecret' => 'zo22y43t1d63okihubfgkg39rdg3pjvl',//Consumer secret registered in server administration
            'callbackUrl' => Mage::getBaseUrl().'/restapi/test/callback',//Url of callback action below
        );

        // Initiate oAuth consumer with above parameters
        $consumer = new Zend_Oauth_Consumer($params);
        // Get request token
        $requestToken = $consumer->getRequestToken();

        // Get session
        $session = Mage::getSingleton('core/session');
        // Save serialized request token object in session for later use
        $session->setRequestToken(serialize($requestToken));
        // Redirect to authorize URL
        $consumer->redirect();

        return;
    }

    public function callbackAction() {

        //oAuth parameters
        $params = array(
            'siteUrl' => Mage::getBaseUrl().'/oauth',
            'requestTokenUrl' => Mage::getBaseUrl().'/initiate',
            'accessTokenUrl' => Mage::getBaseUrl().'/oauth/token',
            'consumerKey' => '3157bsm22p5q80t7zcujfi9uzxafefic',
            'consumerSecret' => 'zo22y43t1d63okihubfgkg39rdg3pjvl'
        );

        // Get session
        $session = Mage::getSingleton('core/session');
        // Read and unserialize request token from session
        $requestToken = unserialize($session->getRequestToken());
        // Initiate oAuth consumer
        $consumer = new Zend_Oauth_Consumer($params);
        // Using oAuth parameters and request Token we got, get access token
        $acessToken = $consumer->getAccessToken($_GET, $requestToken);
        // Get HTTP client from access token object
        $restClient = $acessToken->getHttpClient($params);
        // Set REST resource URL
        $restClient->setUri(Mage::getBaseUrl().'/api/rest/products');
        // In Magento it is neccesary to set json or xml headers in order to work
        $restClient->setHeaders('Accept', 'application/json');
        // Get method
        $restClient->setMethod(Zend_Http_Client::GET);
        //Make REST request
        $response = $restClient->request();
        // Here we can see that response body contains json list of products
        Zend_Debug::dump($response);

        return;
    }
}