Keys are a real thing but are made exclusively for the Asian market. Some of these sellers have found those and were reselling them.
Those keys were sold with similar prices to regular subscriptions on the forum. Some of these sellers are selling those keys for 2, 3, 4 and even 5 times more expensive. And they often even resell the same key to multiple users (as Risky has done)
Those keys were never meant to be sold outside of Asia, as it obviously increase the detection risk. Around 2 weeks ago I've stopped selling those keys, to put an end to those scammers. I'm really astonished anyone would pay so much for a Rust cheat.