For Borderlands 2 there is a SHiFT code until April 19, 2021, which will secure you five golden keys for a short time.
Use these codes to get 5 gold keys for Borderlands 2.
All platforms: CBKTB-X9ZJS-3JX3S-33T3J-55FCS
Expires: April 19th
Redeem golden keys online at https://t.co/7iButjDoDj
– Borderlands 3 (@Borderlands) April 2, 2021
The code is from Gearbox Software and can be used either in-game or on the official website