SELECT 
  category_to_id 
FROM 
  cscart_ble_category_redirects 
WHERE 
  category_from_url = 'products.quick_view?product_id=63815&prev_url=index.php%3Fdispatch%3Dcategories.view%26category_id%3D1911&n_items=63811,63815,63813,63812,63814'

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_ble_category_redirects",
      "access_type": "ALL",
      "rows": 81,
      "filtered": 100,
      "attached_condition": "cscart_ble_category_redirects.category_from_url = 'products.quick_view?product_id=63815&prev_url=index.php%3Fdispatch%3Dcategories.view%26category_id%3D1911&n_items=63811,63815,63813,63812,63814'"
    }
  }
}