SELECT 
  feature_id, 
  variant_id, 
  value, 
  value_int 
FROM 
  cscart_product_features_values 
WHERE 
  product_id = 10173 
  AND lang_code = 'de'

Query time 0.00049

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_id 3 const 77 Using where

Result

feature_id variant_id value value_int
178 6308
22 99
19 5989 0.600
30 240
42 145
21 96
24 107
23 6273
129 5902
75 242
127 5895
128 5899
134 5961
20 6058 1.100
152 6094
152 6095
124 0 5702328433281
149 0 5702328433281
152 6092
152 6096
152 6101