SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '571c8f302c44ce61450750756d323ffc4bad720996fbfe5696cec4427b00177a' 
  AND token = 'XrEEpEVt23ssXwf8IHvWg8ZMZaMBje3v2Oekr3hDpEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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