[adeel_siddiqui]

set `enable_seqscan` = 'off' or set local `enable_seqscan` = 'off'. This will force the pg query planner to use indexes. Experiment with it until you figure out why your query performance deteriorates. Maybe you are doing a lot of updates/deletes? Increase the statistics sampling size? Autovacuum more frequently?

[silon42]

Could one disable statistics completely? Personally, I'd prefer to specify the execution plan manually.