SELECT 
  * 
FROM 
  cscart_faqs 
WHERE 
  object_type = 'category' 
  AND (
    FIND_IN_SET(490, category_tag_ids) 
    OR FIND_IN_SET(490, object_ids)
  )

Query time 0.00090

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_faqs",
          "access_type": "ALL",
          "rows": 10,
          "filtered": 100,
          "attached_condition": "cscart_faqs.object_type = 'category' and (find_in_set(490,cscart_faqs.category_tag_ids) or find_in_set(490,cscart_faqs.object_ids))"
        }
      }
    ]
  }
}