SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '30597666dd28272475cf1171e073f231ae460088eca3cb98d7343c5450911e37' 
  AND token = 'EHs9L36TYdOnI4A/WZU4mjNWj/vPhhviLPALQSdgy4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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