SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '89a57cf633bf8f898fff6ecc92014b5e94585f1e8de7ff12de228d4b8cbbbb65' 
  AND token = 'REBs7WMCRzic6rHmbZEMnex9Ek4MxGQEsDESHZOzEPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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