Row scanned equals to 1, Is the query is optimally tuned ?

A few days ago one of our intern @mydbops reached me with a SQL query. The query scans only a row according to the execution plan. But query does not seems optimally performing. Below is the SQL query and its explain plan. ( MySQL 5.7 ) select username, role from user_roles where username= '9977223389' ORDER … Continue reading Row scanned equals to 1, Is the query is optimally tuned ?