There probably are systems to detect a missile launch of this kind

Some aircraft have missile launch detectors that are based on detecting sudden IR blooms in their vicinity. I don’t think many aircraft have them though.

The Su-25, the aircraft in the video, does have a rear-facing IR dazzler. It basically shines an IR flashlight into the ‘eye’ of any missile following the aircraft. This IR missile, however, hit it from the front/left and not the rear, so that dazzler had no opportunity to attempt to confuse the missile.