I am write a refresh access token rest api, now I facing a problem that I did not know what is the right way to handle the refresh invalid access token request. For example, when the access token not expired, the client request for a new access token. should I give a new access token? or give the old token? or give the token by the expire time, if the expire than greater than 1 hour give the legacy access token, less than 1 hour, give the new access token.