SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f5dea69a6ae74c5ad3365103f5ff041bcf28d8db1ec89af9813c992ff539b17b' 
  AND token = 'oVWhb/RPLZhiK8RapYzqiUVk3/G5uO1R/rgX5eJ1+40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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