Huge MySQL table. Use index to speed queries

Table has 2500000 records. Normal search takes 38 seconds. After indexing it takes only .16 seconds.
> alter table mtp40 add index sn(sort_name, g_srno);

Above creates index sn which gives the query search, above boost.
> alter table mtp40 drop index sn;
This drops the index ‘sn’ from the above table.