Ruby Keys

I have collected Ruby Keys 2-6. I know Ruby Key 1 is in the Golden Cove Bank, but I didn't rob the bank as part of the Snake Gang quest, so is Key 1 now unavailable to me? Also, the map for Mercian Royal Crypt shows 7 Ruby Keys, however, the list of keys in the Wiki only goes up to 6. Is there currently no Key 7?

Yes and yes

Without robbing the bank, you'll miss that key, also the last one isn't available at the moment