SPAppStateQueryJobDefinition
is a timer job registered with the title "App StoreState Update" that runs hourly. According to its description in Central Admin its function is to:
[retrieve] and [apply] updated information on apps from the SharePoint Store, including the availability of updates and disable information.
Basically, it tires to make sure that any apps you have purchased or installed from the SharePoint Store are up to date and updates apps on the farm if needed.
You can turn off the timer job in Central Admin if you aren't using any Store Apps, but I'm not sure if there are any other consequences of turning it off (i.e. impact on other custom apps that are installed in the farm).