If you installed a series of licenses on a workgroup, and want to see which license is installed on a computer, you can use the following command to see last 5 chars of the key installed:
cscript "C:\Program Files (x86)\Microsoft Office\Office15\OSPP.VBS" /dstatus
Before running this command, please make sure you have OSPP.vbs in C:\Program Files (x86)\Microsoft Office\Office15\ folder.
If you have other Office versions installed you may need to change Office15 to the appropriate folder matching your office version.