SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6209211a4e59e4278220caca4631f0a289ef790c27486cf75c4cf4d18bd02fbc' 
  AND token = 'NtFRVERT7KY9ZuYyys5hoTH9Od7yz8FudZEtHdhIq54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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