Using two pins to sum maximum available current
40mA is the absolute maximum current allowed. The recommended steady-state current is 25mA, so you'd need three or four IO pins to remain safe. 

Theoretically, yes, that should be possible. However in practice doing such things is problematic.  You have to ensure that there is no point at which the sensor is being powered by less than the required number of IO pins, which means turning them all from off to on at the same time (doing them one at a time means you start with the full load through just one pin then start sharing it around). That means ensuring that all your pins are on the same port and using direct port manipulation to control all the pins at once.

It is far better, more reliable, and simpler to program, to just slip a simple p-channel MOSFET in there with a pullup on the gate to control the 5V power to the sensor. Pull the gate low and the sensor gets all the power it needs.