QUERY PLAN
Result (cost=2.56..2.57 rows=1 width=4)
InitPlan 1 (returns $0)
-> Limit (cost=0.14..2.56 rows=1 width=4)
-> Index Only Scan using tbl_users_pkey on tbl_users (cost=0.14..48.49 rows=20 width=4)
Index Cond: (id IS NOT NULL)