QUERY PLAN
Aggregate (cost=1.75..1.76 rows=1 width=8)
-> Sort (cost=1.73..1.73 rows=1 width=243)
Sort Key: tbl_comments.created_at DESC
-> Seq Scan on tbl_comments (cost=0.00..1.72 rows=1 width=243)
Filter: ((parent IS NULL) AND ((object_type)::text = '10'::text) AND (object_id = 1))