Complex sentence: As a perfective, the aorist usually implies a past event in the indicative, but while it usually describes the past, it does not assert pastness, and can be used of present or future events.
Split into simpler sentences: As a perfective, the aorist usually implies a past event in the indicative. While the indicative aorist usually describes the past, it does not assert pastness, and can be used of present or future events.