Mac Apps gift cards expire and are they transferrable?

The laptop I bought came with a $100 gift card but I never used it and don't own the Mac anymore, so want to give it to someone as a gift. It's from 2012. Is it still usable and transferrable or associated with my computer and account? It has a scratch surface to reveal the code to redeem it but I don't want to scratch it to determine online if it's still valid. Is there a way to check it otherwise? There's no phone number to call to check it.