Do redeemed codes expire?

So maybe I'm not searching the question correctly, but I can't find an answer to this. If i redeem a code and go to my inbox, it says i can claim the rewards, but what if i want to save that reward for a later time, like an onslaught token for an event, or energy for a campaign event. and if they do expire, does anyone know how long i can save it for? Please and thank you.