SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3b95245b6f385b49b08ce665a4a8e3e5afbe2997407efd880916eb197865e344' 
  AND token = 'uZk3pKj5WrWqir1eOuvz65rXklrDxkXqxXKtFCi79mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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