What response code is suitable for robots if the address is only for AJAX?

Question

Search Engine Optimization

There is an address, for example this: https://example.com/page.php The thing is that it is processed only if it is an xml http request, i.e. for ajax requests. For SEO, having such an address is not very good, because when you go to it, the robot will see 404 or something like that.
Question: what is the right way to send an error code to the robot, saying that there is an address, but it works with PUT, does not work with GET?
I think the most appropriate is 405 code. What do you think?

Answer 1

There is a method not allowed, return it

Answer 2

header('HTTP/1.1 404 Not Found');
exit(0);