While Newtons 2nd law cannot predict the constancy or upper limit of speed of light, c, its generalized version i.e.changing mass with constant acceleration definition can do. In other words, Newtons law holds when an active force applies on a object and cannot accelerated it as long as there is an active change in mass (experimental verified). This explains the constancy of speed of light without need for Lorentzian/special relativistic mechanics.
The podtulate of constancy itself is another issue.. It is reasonable since light is the fastest process and infinite speed makes no sense, mathematically and causally. Still, some consider it an assertion