pgaudit might satisfy your needs, since it would only log SELECT statements on that one table. You'd still have to grep the log file, so the information wouldn't be real-time, but that's probably not important.
That’s a viable suggestion, thanks a lot. Real-time is indeed not necessary, a daily (or even a weekly) cleaning of unused data is sufficient. pgaudit was anyway on the table for some other use cases, so that would fit in nicely.
