When you use EXPLAIN before a mysql query, you can gather details ablout a database table such as possible keys and rows. The data can be useful to determine how a table can be optimized. On the other hand, you can use PHPMYADMIN and analyze the structure and indexes. When you select a table and click structure, the indexes and table information is simple to analyze. The data can be crucial in the adjustment of the tables in order to make optimized queries.
To use explain,
1) Open PHPMYADMIN or mysql console.
explain select * from tablename;