SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd614b21c66fea19fd064b0f3b8e10f4b59f9cd4bd0978ac2974822a57bdbb211' 
  AND token = '9r1cxjL7MwpCE7xf07VICUz3tr7nsyeAAM8b5s1qe1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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