It sounds like in your case you've only manually generated an access token to connect to your own account, and are not using the actual OAuth app authorization flow.
Long-lived access tokens are now considered deprecated, but we don't currently have a plan to disable existing long-lived access tokens. (If that changes, we will of course announce that ahead of time.) That being the case, you can continue using existing long-lived access token(s).
Note though that after the change you won't be able to create/generate new long-lived access tokens.