QUERY PLAN
Limit (cost=1.73..1.73 rows=1 width=105)
-> Sort (cost=1.73..1.73 rows=1 width=105)
Sort Key: created_at DESC
-> Seq Scan on tbl_comments (cost=0.00..1.72 rows=1 width=105)
Filter: ((parent IS NULL) AND ((object_type)::text = '10'::text) AND (object_id = 1))