Yes (At least as STE+ on Delta) - Normally when you check in at OTP (in Sky Priority lane) they give you the invitation card for the lounge. It is the Tarom business lounge on the 2nd level (up the escalator). - I think there is second lounge there too - but have not used that one.

Problem I find with OTP is that is difficult to check in more than one hour before your flight (either with KLM or AF).

Small though the lounge is there is normally a good selection of snacks and beverages.
(And if you are a smoker - there is a smoking section in there).