SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a453d009ab1f181baa5e5ecdb6ec8e88660ca8bfcea5c8382b616f0ae4cd3794' 
  AND token = 'MAMeoZqWsNPDJ5K6KT/+nLauVk/drPch4sFpj/mV23Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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