SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c85ac105fe5762f071a61cc6046241606c396aee77b9ddec731e77be5407e08' 
  AND token = 'Zran3jYEb6xClcojxHf5hLyezH1p0dVBFfcwUhLjb1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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