SELECT 
  pf.feature_id 
FROM 
  cscart_product_variation_group_features AS gf 
  INNER JOIN cscart_product_filters AS pf ON gf.feature_id = pf.feature_id 
WHERE 
  pf.feature_id > 0 
  AND pf.filter_id IN (315) 
LIMIT 
  1

Query time 0.00012

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables