SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eaa87c3e6b2d79950b86154d435fbf59d4fa76715921e287f2da8c0da4788c9' 
  AND token = 'l3M042VFM8UrU/zJv2MnhIqTfqhsu4qmgbXgI6r9nXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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