SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f70f8d1a041bae85a66679a5d735b8efc829d850b9be642c10da1b8ddd33231e' 
  AND token = '39PMMBMtQhtp9g8UR9wIhYTTKwjI7ACU42omKhdhRMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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