SQLite Forum

Performance Issue: How can I increase a performance?
How many of the 33 million rows are returned by the query which took 150.7ms? 
Have you tried adding item_id to the index, which would save having to go back to the base table to further restrict the results. For example, there might be 10 million rows matching list_id and modified_date_time, but only a tiny percent might also match item_id.