you have to load through a collection:
$product = Mage::getModel('catalog/product')
->getCollection()
->addAttributeToFilter('entity_id', 1684)
->addAttributeToFilter('advertise_id', 283)
->setPage(1, 1)
->getFirstItem();
if ($product->getId()) {
...
}
Hope it helps.
EDIT
To solve the problem of advertise_id
attribute not belonging to flat table, try this snippet:
$attribute = Mage::getSingleton('eav/config')
->getAttribute('catalog_product', 'advertise_id');
$productCollection = Mage::getModel('catalog/product')
->getCollection();
$productCollection
->getSelect()
->join(
array('attributeTable' => $attribute->getBackend()->getTable()),
'e.entity_id = attributeTable.entity_id',
array('advertise_id' => 'attributeTable.value')
)
->where("attributeTable.attribute_id = ?", $attribute->getAttributeId())
->where("attributeTable.value = ?", 283)
;
$product = productCollection
->addIdFilter(1684)
->setPage(1, 1)
->getFirstItem();
if ($product->getId()) {
...
}