Yes, if an object has zero mass and there is no external force acting on it, it will move with a constant velocity in a vacuum with no friction. This is known as Newton's first law of motion or the law of inertia.
According to Newton's first law, an object at rest will remain at rest, and an object in motion will continue to move with a constant velocity in a straight line unless acted upon by an external force. Since the object in question has zero mass, it does not require any force to maintain its velocity, and therefore it will continue to move with a constant velocity in the absence of any external forces or friction.