SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c5a1a864c6cccc347e5715b26d455b894a8ca97d10e9bc3af657f70e32979be' 
  AND token = 'sAV+PH8OZaVSnJ8UhJnRuwxe5lKJh1/ztb1FgKhg2vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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