Just go Afk in Gun game. Leave your console on (Make sure to turn off power saver on your console), and you'll get xp towards your Cryptokeys. What's cool is that you won't get kicked for inactivity in Gun game, and you get points just for being in the match. In otherwords, go do your daily routine, then come back to the game and you'll have keys to spend in the Black Market. Happy expoliting ladies and gentlemen!