SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9483439bc2de7dad3eb9e1deef9a0893b38920841702cf762ed76cb393d8eb70' 
  AND token = '/Ybs9Sms8fE7YfnBS5m9+EnUxAX7iBOQT106IAf0d5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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