SELECT 
  feature_id, 
  variant_id, 
  value, 
  value_int 
FROM 
  cscart_product_features_values 
WHERE 
  product_id = 4939 
  AND lang_code = 'de'

Query time 0.00040

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_product_features_values ref lang_code,product_id,product_id_idx,product_feature_idx product_feature_idx 3 const 63 Using where

Result

feature_id variant_id value value_int
24 107
30 128
42 149
127 5895
128 5899
129 5903
135 5964
135 5963
135 5968
135 5967
136 5976
136 5972
176 6271
176 6270
176 6262
176 6260
178 6306