How to find my Google Play Services Android BASE64_PUBLIC_KEY

My problem was that I wanted to test before the app was uploaded on to the play store. By starting to create a Play listing for the app (no need to fill anything out) it is shown as Draft. At his point the Services & APIs section becomes available and the key can be copied.

UPDATE: http://developer.android.com/google/play/licensing/licensing-reference.html states that you can no longer test Licencing unless it has been published to at least Alpha.

So, Ignore any documentation that states you can test unpublished apps. Also, ignore the text in the developer console under where you can set a test response in the settings that says: "All accounts listed above will get the Licence Test Response. The account owner (but not the other test accounts) will also get this response for applications that have not been uploaded to Google Play yet."

Select your app > Dashboard > Monetize > Monetization setup

Now After new Console Update Its Under

 Monetization setup > Licensing 

The Google Play console has changed recently.

The way to find it now it Developer Console > Select your app > Development Tools > Services & APIs.