Because you have a clustered index on that table it doesn't really matter what you put in the key columns of that index; meaning Id
is there free of charge. The only thing you can do is include
everything in the included section of the index to actually have data handy at the leaf level of the index to exclude key lookups to the table. Or, if the queue is huge, then, perhaps, some other column would be useful in the key section.
Now, if that table didn't have a primary key then you would have to include
or specify as key columns all the columns that you need for joining or other purposes. Otherwise, RID lookups on heap would occur because on the leaf level of indexes you would have references to data pages.