Actually for any key that can at least activate one thing, even if you have all the rest, it'll be redeemed and marked as used. In fact some subs include things that you don't know, you'll not see, yet don't have (e.g. a package for workshop) and that once made me lose one valuable key thinking it would give me the usual "you've already acquired that product" error. The key will not be redeemed only if you have every depot that the key activates, and I even think there might be exceptions to that and it'll be redeemed anyway.

In this specific case, if you have the base game, you can redeem this key which will enable all the DLCs in the bundle.