What criteria is being used to determine if they're watched/unwatched, and if you already know that status why bother separating them into separate folders? And which folder(s) are they in before they're moved by Hazel (presuming that's what you're wanting it to do)? And which software is used for playback? It's not totally clear to me what you're trying to accomplish.
Using an updated access time to decide if a show's been watched wouldn't be reliable, e.g. what if you stop after watching a few minutes and still want to consider it unwatched.
Seems to me it might be easiest just manually move files to a "watched" folder when you decide they've been watched.