* Did you run `ANALYZE`? * What is the result of adding `EXPLAIN QUERY PLAN ` in front of your select query? * What is the disk type, SSD I hope? * your index of `(list_id, item_id)` still means scanning for modified_date_time, how many rows does it need to scan? Did you try adding the index `(list_id, item_id, modified_date_time)`?