SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99267a43016b1f55e9b381f28a49785740ef148831ac5f55d1740422a572908a' 
  AND token = 'sNRupfWRW83SzsmxACK87x769IHC9+M0mfIiO363QQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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