Talk:Crimson Chest/@comment-26447375-20151016232726/@comment-3157150-20151017015220

Nope, you just need to be within the reaches of what the game recognizes as a Crimson Biome. It can become impossible for the keys to drop if the location where you're farming crosses over with another biome (that has a key that can drop, like being too close to the hallow when farming for crimson/corruption keys).