SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab5a1fd0444a804c03f7c079b0b9a5404d255e5d20be87c34e4920f3bfb1075' 
  AND token = 'i/WXVK81pBvaemQDh7YgJcIE2GW9h7EY+l4k7nNHvdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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