wkq to xlsx conversion is most likely sought by users that want to recover data from very old Corel Quatto Pro for MS-DOS spreadsheet and convert these to modern format.
Maybe the modern versions of Corel Quattro Pro can still access .wkq files, but that is uncertain. The only alternative is to download old version of the tool from some abandonware website and launch it either in DOSBOX or MS-DOS virtual machine to export the sheets to some common format, such as CSV that can be imported to Excel. Otherwise it is unlikely that some kind of converter for this exists.
Updated: September 11, 2023