How fast were the ancient war horses?

Converted from the speed of modern horse racing 1000m, the fastest thoroughbred horse is 60km/h, and Ilima, Sanhama and Mongolian horses are around 45-48. If it is a long-distance race, the endurance of the latter three is good, which should be 35-40 km/h. Considering that horses are now improved by hybridization, and ancient war horses rarely come from Central Asia, the average speed of ancient war horses should be only 30-35 km/h.