The motion of a body with constant speed in a circular path is said to be accelerated,
because it is moving with uniform speed, but not with uniform velocity, as velocity is a vector quantity, it can be represented in magnitude as well the direction. Though the magnitude doesn't changes, the direction changes in a circular motion, so the object is said to be in acceleration.
Hope this will help u.
In a circular path the direction changes at every moment and thus the velocity also changes. So though even if a body is moving with constant speed in a circular motion, it will be called an accelerated motion. :)