If a location is in the staging area when it get is las progress token, does it still consider explore or does it have to be the active location to be consider explore?

Anytime a location recieves the last progress token needed it is considered explored. Being the active location is not a pre-requisite for exploration. It just means that excess willpower from questing is applied to the location before the current quest stage.

So if you had an Ancient Mathom on a location in the staging area and you place the final progress token on it from say a Snowborn Scout or Northern Tracker then you get to draw the three cards.

Thank for the quick answer