It depends on how you want to get the token. The current OAuth2 URL to get the tokens is https://account.lab.fiware.org/oauth2/token. This is the central authority for authentication, if you are accessing any common GE, but you will need to register your application in FIWARE Account and use your application credentials and some OAuth2 grant to get it.
If you want to get the token for the global instance without using a registered application, the URL you have mentioned contains a token service that can give you a valid token for your user and that purpose. You can test it (and see an example) with the following script:
https://raw.githubusercontent.com/fgalan/oauth2-example-orion-client/master/token_script.sh