Non-tokenized but indexed fields (ex. keywords) stores data "as is". So 'framework.zend.com' is stored as 'framework.zend.com'

If we try to find this value: "url:framework.zend.com", query parser will break it into three different terms: 'url:framework', 'url:zend' and 'url:com'. No one of these terms matches 'url:framework.zend.com'

So we get empty result set for this query.

There is no way to search through non-tokenized fields with current query language now. It's possible with API methods:

$term = new Zend_Search_Lucene_Index_Term('framework.zend.com', 'url')
$query = new Zend_Search_Lucene_Search_Query_Term($term);

$hits = $index->find($query);