SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '280d4cf5ee7f92d60891b362c63a6d830692e08208d735ac1b329b912711181e' 
  AND token = 'TH8hOtKzd2qQ9AcaVW3YA8aVdPDhGGyPDZ+0vR6c3vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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