Which token are you trying to retrieve? I don't use the APIs much, but once you have a user with an authentication key you shouldn't need new access tokens each time to retrieve data, that seems in-efficient...
As with other systems, I would think that once you have generated a token, that would be a permanent item that you would code into your jobs that authenticates your usage of the API... I've never seen a system that needed a new generation for each usage.. that would be like forcing you to change your password every time you log into a website.....