SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32304175421ced07dcb901ff22a18ce9aa813d1c60cb8daf560ae35df57b179e' 
  AND token = '/KvRlQ9j8R09C6Dp0fm9+boQTf7vaZ4VH1qejMYu3G8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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