SELECT 
  feature_id, 
  variant_id, 
  value, 
  value_int 
FROM 
  cscart_product_features_values 
WHERE 
  product_id = 1310 
  AND lang_code = 'de'

Query time 0.00070

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 111 Using where

Result

feature_id variant_id value value_int
178 6311
42 149
30 6124
135 5964
24 107
127 5895
128 5899
129 5903
59 5877 4.000
134 5960
135 5963
152 6094
152 6093
152 6092
152 6091
152 6090
136 5972
152 6089
152 6088
152 6095
152 6096
152 6100
152 6101
152 6105
152 6106
136 5976
176 6261
19 106 1.000
135 5968
135 5967