facebook token expiration issue

Question

I've integrated facebook with my app using facebooker2 and Mogli. Now offline_access is removed from the facebook. I'm able to get token but its getting expire in 2 hrs, also If user get logged out from facebook, Its also get expired.

I wanted to renew the tokens but I can not do that by following code

https://graph.facebook.com/oauth/access_token?             
client_id=APP_ID&
client_secret=APP_SECRET&
grant_type=fb_exchange_token&
fb_exchange_token=EXISTING_ACCESS_TOKEN 

As I could not get when user get logged out from the user. If any how I can know when user get logged out from Facebook , still I can not exchange the tocken as its already get expired. and access_token only works before the expiration of a token.

Any Idea, if I have 60 days expiration token or renew the token before get expired.

Thanks in advance for any help you are able to provide.