The master can never tell you the current state of any node, but it can tell you the state reported by that node when it last made a catalog request, in the form of the reported node facts. That would involve
a node query instead the catalog query to which you linked. The docs are rather vague on what exactly the result of a request to that API will be, though.
You could also consider opening up access to PuppetDB's HTTP API, which is a bit more clearly defined. You can then issue
a facts query to retrieve the latest facts recorded for the machine of interest.
John