Last tested: Oct 16, 2020
Query created date is the time that a specific query was first run. The history created date will have a new row every time that query is run.
So if you run a specific explore for the first time, the history and query created date will be exactly the same. If you run the same query (same fields, filters, vis config) a couple days later, you'd have another, new history row with a new created date two days later, but the query created date would be the same.