Use this SQL to find the last time a tables was used in SQL Server Database.
SELECT
DB_NAME(ius.[database_id]) AS [Database],
OBJECT_NAME(ius.[object_id]) AS [TableName],
MAX(ius.[last_user_lookup]) AS [last_user_lookup],
MAX(ius.[last_user_scan]) AS [last_user_scan],
MAX(ius.[last_user_seek]) AS [last_user_seek]
FROM
sys.dm_db_index_usage_stats AS ius
WHERE
ius.[database_id] = DB_ID()
AND ius.[object_id] = OBJECT_ID('YourTableName')
GROUP BY
ius.[database_id],
ius.[object_id];