Energy=power x time 

E= 0.124 x 1 

E= 0.124 watt/h

 Hi Devendiran

I confused a little bit because Power is 0.124 Watt/ sec or 0.124 Joule

and your answer is 0.124/h

So, could you please explain more for me.

If your meter reads 0.124 watts for one second, then you have 0.124 watt seconds. If you read 0.124 watts for one hour, then you have 0.124 watt hours. 3600 watt seconds = 1 watt hour.

the energy consumed by the sensor in W.h = 0.124 x 1 = 0.124 Wh.

No need to convert it to Joule (W.sec) because Wh is commonly used to measure power consumption and you can even find batteries with energy capacity in Wh.

If you want to compare with battery capacity, then battery capacity in Wh = 0.45 x 3.7 = 1.66 Wh

then you can run your application up to 1.66/0.124 = 13.4 hour

But this is short answer. Detailed answer: it also depends on the type and efficiency of DC-DC converter of your sensor. For example if you have switching DC-DC converter with typical efficiency of 85%, then the running time is: 13.4 x 0.85 = 11.4 hour