I'm uncertain how you have the account with no stake. Guessing the esteemapp has something to do with it as it is set as your recovery.

Here is a video on how the keys work.

It will refer to Steem, but it is the same here.

3 of your 4 keys will start with a 5. The master key will start with a P. Don't store these on your computer, and never use your master key unless you need to change the keys due to hacking. Unless doing something with the wallet, only use your posting key. The active key is used for wallet transaction and if a hacker gets it they can take your coins if not powered up.

If you didn't make note of these keys when you created your account, you probably need a new account.