Future Industry 4.0 systems will make use of independent and cooperative assets. In order to use the services of the assets, a digital representation must be available. The Industry 4.0 Asset Administration Shell fulfils this task. It contains all the properties and capabilities of the asset. Currently, retrieving related information over HTTP/REST is complicated because there is no query interface. We propose the development of a universal query interface based on the existing API definition for the Asset Administration Shell. Different approaches are discussed and a conceptual approach using GraphQL is presented.