SELECT 
  product_id 
FROM 
  cscart_product_descriptions 
WHERE 
  lang_code = 'en' 
  AND (
    product LIKE '%镀锌圆钢镀锌层标准 filetype:doc%' 
    OR full_description LIKE '%镀锌圆钢镀锌层标准 filetype:doc%' 
    OR meta_keywords LIKE '%镀锌圆钢镀锌层标准 filetype:doc%'
  ) 
LIMIT 
  5

Query time 0.50678

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 146.6488038,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "ALL",
          "loops": 1,
          "rows": 871563,
          "cost": 146.6488038,
          "filtered": 100,
          "attached_condition": "cscart_product_descriptions.lang_code = 'en' and (cscart_product_descriptions.product like '%镀锌圆钢镀锌层标准 filetype:doc%' or cscart_product_descriptions.full_description like '%镀锌圆钢镀锌层标准 filetype:doc%' or cscart_product_descriptions.meta_keywords like '%镀锌圆钢镀锌层标准 filetype:doc%')"
        }
      }
    ]
  }
}