SELECT 
  feature_id, 
  variant_id, 
  value, 
  value_int 
FROM 
  cscart_product_features_values 
WHERE 
  product_id = 10223 
  AND lang_code = 'en'

Query time 0.00046

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 50 Using where

Result

feature_id variant_id value value_int
134 5961
22 99
30 6124
127 5895
128 5899
129 5902
42 145
23 102
20 6058 1.100
24 107
21 96
178 6311
149 0 5901337173618
124 0 5901337173618
19 241 0.700