Hi! What type of index to use?

Table structure:

Day_Id int, Location_Id int, Prod_Id int, Sale_Flag tinyint ...

Day_Id, Location_Id, Prod_Id - is primary key

Sale_Flag - a flag (0 or 1) indicating whether sales by Day_Id, Location_Id, Prod_Id

Table Records count - 7 465 699 304

using measure as SUM(Sale_Flag):

Day_Id, Sum(Sale_Flag) or Day_Id, Sum(Location_Id) ...

I have created 2 index this flag - HNG (917M) and LF (1.65G)

What type of index to use ?

What type of index is preferable to use ?

Perhaps both ?

or remove one ?