Ok I figured it out, I used wrong clock - I cant use Event tick - this type need proper clock and then pick value from that is easy.
To describe problem for others looking answer: Create Material Parameter Collection, Create scalar, Create curve, Make clock from below, Make curve variable, Connect it to Get Float Value, Connect time from before subtraction and you have pretty good working 0-1 mask in material.
Thanks Galagast for help!
Link to guy who made proper clock that solve all problems: Multiplayer Day Night Cycle Tutorial in Unreal Engine 4 - YouTube