SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f82ab423f105713de52e612064fa2777540269b100ffbc92c13d1587a87ca09' 
  AND token = 'AP/acarOrqAsZtZAd9zGrxwYoK/rqKPQSLUGgo/C3bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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