Lost my recovery key for two-step verification

I quote:

What if I lose my Recovery Key?

You can replace your Recovery Key any time by visiting My Apple ID:

1. Select “Manage your Apple ID” and sign in with your password and trusted device.
2. Select “Password and Security”.
3. Under Recovery Key, select Replace Lost Key.

Note: When you create a new key, your old Recovery Key is no longer usable. See this article for more information.

End quote. When you get your recovery key make sure to keep a copy of it in a safe place (and not on your computer). If you were to lose both the Recovery key and your Trusted Device (or forgot your password) you would be locked out of your Apple ID forever - Apple would not be able to help you.

Click "Lost your Recovery Key?" to the left of the Cancel button.