Two codes for 5 keys each.
KWCT3-SSFWX-XHBF3-3TTJB-WXXF9 - expires 27 April 2:00pm
5WKBT-FHXKR-XH3FT-J33BT-T9JWR - expires 28 April 3:00pm
You don't need to own the game to redeem the keys. These are not codes to unlock the game, they're only for unlocking chests to receive special loot. Direct link to redeem at SHiFT is https://shift.gearboxsoftware.com/rewards, or redeem through your respective platform (multiple redemptions possible this way).
Thanks to dealbot for the nudge.