MariaDB [test]> CREATE or replace TABLE `t1` (

    ->   `col1` bigint(20) NOT NULL AUTO_INCREMENT,

    ->   `col2` varchar(50) COLLATE utf8mb4_unicode_ci NOT NULL,

    ->   `col3` varchar(50) COLLATE utf8mb4_unicode_ci NOT NULL,

    ->   `col4` varchar(50) COLLATE utf8mb4_unicode_ci NOT NULL,

    ->   `col5` varchar(100) GENERATED ALWAYS AS (concat_ws('\n',`col3`,`col4`)) STORED,

    ->   PRIMARY KEY (`col1`),

    ->   KEY i1 (col2)

    -> ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

Query OK, 0 rows affected (0.02 sec)

MariaDB [test]> DELIMITER $$

MariaDB [test]> CREATE PROCEDURE prepare_data()

    -> BEGIN

    ->   DECLARE i INT DEFAULT 1;

    -> 

    ->   WHILE i < 500 DO

    ->   INSERT INTO t1 (col1, col2, col3, col4) VALUES (i, 'AAA', '', ''); 

    ->   UPDATE t1 SET col3 = 'BBB', col4 = 'CCC' WHERE col1 = i AND col2 = 'AAA';

    ->     SET i = i + 1;

    ->   END WHILE;

    -> END$$

Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> DELIMITER ;

MariaDB [test]> CALL prepare_data();

Query OK, 1 row affected (5.03 sec)

MariaDB [test]> select * from t1 where col1 = 499\G

*************************** 1. row ***************************

col1: 499

col2: AAA

col3: BBB

col4: CCC

col5: BBB

CCC

1 row in set (0.00 sec)

MariaDB [test]> select version();

+-----------------+

| version()       |

+-----------------+

| 10.2.12-MariaDB |

+-----------------+

1 row in set (0.00 sec)