SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b5347bc9c760fa997efff118c9dd27fd235d047252f87ee0f7f2b5c9e06baea' 
  AND token = 'Q0BhdX9r3iJd+uFd1aoMUy6PUiP7D/jSPzf4ZLPnNYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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