How can I get the group id of a node using tokens? I try to use [node:og_group_ref], but that gives me the group node title and I need the GID, I am sure there should be a way to get it but I haven't found it
In Organic Groups 7.2 the Node idea and Group id are the same. So if you are using views you can do the following:

Add field "Content: Nid" and exclude if from display.
Any field arranged below the above can use [nid] as a rewrite giving you the Group ID. 

Does this help?