Create index to text type column

If you are using innodb, you should create a FULLTEXT index.

FULLTEXT indexes are created on text-based columns (CHAR, VARCHAR, or TEXT columns) to help speed up queries and DML operations on data contained within those columns, omitting any words that are defined as stopwords.

Please see the MySQL FULLTEXT documentation.

mysql> CREATE TABLE opening_lines (
   id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
   opening_line TEXT(500),
   author VARCHAR(200),
   title VARCHAR(200),
   FULLTEXT idx (opening_line)
) ENGINE=InnoDB;