Slow Query, when using LOCATE String Function

SELECT attr_client_name

FROM tbl

WHERE (LOCATE(attr_client_name, "joe70700") > 0);

# Time: 210319 14:19:04

# User@Host: admin[admin] @ localhost [127.0.0.1]

# Thread_id: 18  Schema: test_slow  QC_hit: No

# Query_time: 0.021040  Lock_time: 0.000110  Rows_sent: 5  Rows_examined: 100000

# Rows_affected: 0  Bytes_sent: 152

# CREATE TEST TABLE

DROP TABLE IF EXISTS tbl;

CREATE TABLE tbl (

  Id bigint(20) NOT NULL AUTO_INCREMENT,

  ClientDocument longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_bin DEFAULT NULL CHECK (json_valid(ClientDocument)),

  attr_client_name varchar(255) GENERATED ALWAYS AS (json_value(ClientDocument,'$.Name')) STORED,

  PRIMARY KEY (`Id`),

  KEY idx_tbl_name (attr_client_name)

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

# CREATE TEST PROCEDURE

DROP PROCEDURE IF EXISTS tbl_fill_json;

CREATE PROCEDURE tbl_fill_json (IN cnt int)

BEGIN

DECLARE

	p1 int DEFAULT 0;

DECLARE

	val longtext;

	label1: LOOP

		SET p1 = p1 + 1;

		SET val = concat('{"Name":', '"Joe', p1, '"', '}');

		IF p1 <= cnt THEN

			INSERT INTO tbl (ClientDocument)

				VALUES(val);

			ITERATE label1;

		END IF;

		LEAVE label1;

	END LOOP label1;

END;

# STORE 100,000 Records

call tbl_fill_json(100000);

# TEST QUERY 1

explain 

SELECT attr_client_name

FROM tbl

WHERE (LOCATE(attr_client_name, "joe70700") > 0);

# TEST QUERY 2

explain 

SELECT attr_client_name

FROM tbl

WHERE attr_client_name LIKE 'joe70700';

explain 

SELECT attr_client_name

FROM tbl

WHERE (LOCATE("joe70700", attr_client_name) > 0);