SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48e523dfc3942ed5dcd57c1b4763e97a8963d37c24bdf452530959ec270eed99' 
  AND token = 'A6J/UFL+4NNSYufRGdVkjfIozAngFjrrl6BTPeObt3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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