Is it possible to use different tokens in metatag based on content type Lets say I have the summary field enabled on article type but not on page type and then I setup meta tag descriptions to use the token [node:summary] would is be possible to do something like if [node:summary] doesn't exist or is empty than use [node:body] ?

Otherwise i was would most likely need to add the summary field to page types and fill the summary field for all the pages that didnt have it.
In Drupal 7
When you configure Metatag, you can click on + Add default meta tags and this will allow you to set them up by Content Type.


You will see this gets added to the config tree. Simply now edit the content type you just added.
Bonus/Extra Info
If you need to alter only specific nodes, edit your node and scroll down to the end and select the Meta tags tab.