Old Lotus 1-2-3 program used many different file types throughout its existence and some are still supported in modern programs, but such support is phasing out with every version.
Your best bet for wki to 123 conversion would be to find the original program somewhere on internet (check sources for old apps), or to use some programs that may still support and open .wki or .123 spreadsheets. As far as we know, certain versions of Corel Quattro Pro or OpenOffice Calc might still support this format, but this might not be the case for some more recent versions of these programs.