Geocoding is not one of the services available through the developer console at this time, which is why the key does not work (note that geolocation is not the same as geocoding).
Currently you'd need to use client side geocoding (for example in the JS Maps API) -- or purchase more server side geocoding with a maps for business license in order to increase this quota.
The fact it says the key is expired is misleading, and I'll file a bug for that.
EDIT/UPDATE: The geocoding service is now available through the developer console.