SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9ce7b5563032921a454d957ac65ccff5d8700de2e361fe6c4189cf7fb5e08038' 
  AND token = '/DTogbV1rK5iq6podIPqldlksX9sFskZL9MQ4j1x2qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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