SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'de8347449b7adbf8595cfe4f801be9b7206e4bb599e55825353471c0609b815b' 
  AND token = 'yg2wv36mq48qyiWkccbThJoh3mRKejCSLnZugz8RzPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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