select json data in mysql

SELECT * FROM `notifications` 
WHERE JSON_EXTRACT(data, "$.user_name") = 'sky'

demo data notifications.data

 {"id": "1", "user_name ": "sky"} 
 {"id": "2", "user_name ": "Joe"} 
 {"id": "3", "user_name ": "Tom"} 
 {"id": "4", "user_name ": "May"}