SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ff727f0bbd70c6076a991b06b60d575b8928e122a6d315bfa1eef99e1732f73' 
  AND token = 'kvGOpIxNl4+jhnQGobQONJzkgqJw8bQ3n73OfBChDtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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