Yes, you can keep a live session open for as long as you would like. You can find which sessions are still open by navigating to your sessions tab. The sessions with a blue dot on the left are still open and can be joined:
If you want to schedule when a session will end, you can do so by using the session scheduler. Schedule your session with a few easy steps:
Navigate to session settings and select session scheduler.
2. Select the timeframe you would like to make your session available.