yes you do burn more calories when doing a low intensity workout
but here is catch!!
you are directly burning "fat" when doing a low intensity workout
and you burn carbohydrates when doing a high intensity and those are quick sources of energy your body has, so when you are resting , your body then converts fat into the ready store of energy called carbohydrates, so in that way you burn calories for a longer period of time than doing low intensity
overall high intensity will burn more calories not necessarily "during" the workout but "after" the workout