Why when I use variables on SQL the Database Engine avoid the indexes?

I'm improving our SSIS process passing the variables through a declare and I found this: Here you have the plan execution using variables brentozar.com/pastetheplan/?id=rkSxs7VPv for the following statement:

select *
from fact_Venta
where Data_ID >= @data1
and Data_ID =@1 
AND [Data_ID]<=@2

As you can see, when I use the declare SQL Database Engine doesn't use the index. The index used is a non-clustered for the column used on the where. Both executions were on the same server, with the same set options and at the same time executed.