Is it possible to pursue a PhD while working full time and living in another country?
In regard to living in another country, at least in the US, most universities have a residency requirement (for example, Cornell's) that means you have to live there for some amount of time.

As far as working full-time, sure, it can be done. It will be extremely difficult and it may be a challenge to convince an advisor to work with you. A PhD is hard enough doing it full-time. Part timers seem to take 7-9 years in my field and finish with fewer publications.

Something that a potential advisor will ask you is why do you want a PhD if you already have a job and are going to continue working in that position? A PhD trains you to do research but you aren't really doing research as a CTO are you? If you just want knowledge in the field, then take some classes or study on your own.