Yes, mintime is supported. The value for mintime is invalid. The example request you provided is giving the timestamp in milliseconds instead of in seconds as mentioned in the documentation. Some of the API endpoints require seconds, and some require milliseconds. Which one is required is noted for each endpoint that has a min/max time param.
You'll note, however, neither maxtime nor limit are mentioned as parameters for retrieving admin activity logs.
Duo, not DUO.