Max. speed of the Kh-22 is M 4,6 (4.900km/h)
The Kh-22 and Kh-22M are mach 3 rocket powered missiles.
During the 1990s the Russians offered it as a testbed for scramjet and other engine mount testing (ie put your test scramjet motor on the nose and launch it to mach 4.5, and then run your scramjet motor for testing) with a special version with most of the guts missing.
Also in the late 1990s they improved both rocket motors on the weapon to improve the flight speed of the weapon to Mach 4.5 and increased its range by double to over 800km, but although looking identical it is called Kh-32 now.
The Kh-22M also flew at about 22km altitude, while the Kh-32 operates at about 40km altitude...