Astro Boy began as a Japanese comic (manga) in 1952 and then became an anime cartoon before anybody knew what anime was. The cartoons of the 21st century Pinocchioish robot boy were dubbed in English and syndicated in the U.S. starting in 1963. I do remember one time-travel episode in which Astro Boy stopped a time-traveling collector from the future who was after ancient animals and people for his zoo; and I suspect there was more time travel in the manga and later U.S. cartoons.