WP_Query not returning correct result with meta_query parameter

I think you’re using wrong keys for meta_query array, also it expects nested arrays, even if you only have one query. Code below should help.

        $args = array( 
            'meta_query' => array(
                array(
                    'key' => 'is_url', 
                    'value' => 'yes', 
                    'compare' => 'NOT LIKE'
                )
            ),
        );