Yes of course. Range searches will benefit from an index, just as much as equality searches.
Quoting from the MySQL Reference Manual :: How MySQL Uses Indexes:
B-Tree Index Characteristics
A B-tree index can be used for column comparisons in expressions that use the =, >, >=, <, <=, or BETWEEN operators. The index also can be used for LIKE comparisons if the argument to LIKE is a constant string that does not start with a wildcard character.
In some situations, the optimiser may decide not to use the index if the range will end up to be too big, as a table scan might actually be faster. Use EXPLAIN
to see which (if any) indexes will be used on your query.