Please refer to the following article:
Keyboards which have standard MIDI In/Out ports can be connected to a Mac, as long as your Mac is equipped with a MIDI interface that is compatible with your operating system, and you have the appropriate cables to connect the keyboard to the MIDI interface.
Keyboards with USB connectivity will only work with Mac if they are "class compliant". No driver is needed for these keyboards.
If you have a keyboard that requires installation of a separate USB driver, then this driver is only available for certain versions of Windows. Casio does not have a Mac driver available for these keyboards.