Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c40b59c89986d2e8e7ff6759abf7bf34dd994bbdd091d676e79410a8bd2df23d' 
  AND token = 'RhdJ3ZIU9IhDEv90g256eQ7scfRsIcZ9oFmqnV7P1ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}