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SELECT 
  * 
FROM 
  cscart_csc_virtual_categories_conditions 
  LEFT JOIN cscart_category_descriptions ON cscart_category_descriptions.category_id = cscart_csc_virtual_categories_conditions.category_id 
WHERE 
  cscart_csc_virtual_categories_conditions.is_virtual = 'Y' 
  AND cscart_category_descriptions.lang_code = 'en' 
ORDER BY 
  category

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "Impossible WHERE noticed after reading const tables"
  }
}