You can check the approved use for an HDB shophouse through the URA's free Electronic Development Register. This is an electronic repository for information on all Written Permissions granted or rejected by URA from 2000. Alternatively, you can submit a search enquiry to URA for a fee of S$53.50 (including GST) per property unit, and the result will be received within 2 weeks.
For more information, you can visit the URA website
here.