SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '441f6c899b622395ccac234616707af5f554c856088d50c849e4d600a2808726' 
  AND token = 'SwTGRKdu6FenC1mjSBlicpq+S/Ba+hi7WKOqNPvTQfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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