Disconnected run scanner query

hyperdash_free=> explain analyze SELECT sdk_run_uuid FROM heartbeats WHERE last_seen_at < NOW() - INTERVAL '30 seconds' AND eligible_for_disconnect_scan = true AND run_completed = false LIMIT 10;
                                                                        QUERY PLAN                                                                         
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 Limit  (cost=0.43..2.64 rows=10 width=16) (actual time=191.810..191.810 rows=0 loops=1)
   ->  Index Scan using heartbeats_last_seen_at_idx on heartbeats  (cost=0.43..15066.99 rows=68307 width=16) (actual time=191.809..191.809 rows=0 loops=1)
         Index Cond: (last_seen_at < (now() - '00:00:30'::interval))
 Planning time: 0.089 ms
 Execution time: 191.837 ms
(5 rows)