I see that there are HDL implemetations for FPGAs fo that old keyboard-display controllel chip. Use Google and you will see (for instance search for "intel 8279" )
If you are making a redesign of some device using that chip, you can either use one such implementation or program a microcontrollel to do the same functions. Keyboard scanning is not very hi-tech stuff.
If this is for a replacement as a spare part, I think you have to find some old chip -- either as a part from some seller or slaughter some antique equipment using it.
Good luck,
Ted