SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b5f8661b4a044e4f69ff647874cce50949fd9c98f1e472783f203a516c40958' 
  AND token = 'KupsggKrshmGXzrOyPJAjGU+dLLpuzTqOS87LVD4mhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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