Quick Question: Steam Key EU?

There seem to be no limitations, according to steamdb

You mean you activated the key via Steam already? Or did you mean something else? I used a vpn last time I redeemed a game (Russian). Ran the VPN first, logged into Steam then activated the game. Then logged out and disabled the VPN and logged back into Steam and my game was playable. This was some time back and I couldn't tell you what VPN to get for your EU game. For future reference, if you buy a Russian CD Key refer to this page: http://cdkeyprices.com/guides/activate-russian-cd-key