That power supply will work. They recommend more than the card needs because manufacturers know people will buy the cheapest power supplies possible, so if they said the card works with a 400W PSU most customers would use a cheap 350W PSU because, hey, 350W is almost 400W right?
I'm not saying this is you Mr 'I have an i7 6700k and want to buy a 1070 but have a 450W power supply', but there are people like that out there.