SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  fv.position, 
  fvd.variant 
FROM 
  cscart_product_features_values AS pfv 
  INNER JOIN cscart_product_feature_variants AS fv ON pfv.feature_id = fv.feature_id 
  AND pfv.variant_id = fv.variant_id 
  INNER JOIN cscart_product_feature_variant_descriptions AS fvd ON pfv.variant_id = fvd.variant_id 
  AND fvd.lang_code = 'en' 
WHERE 
  pfv.feature_id IN (
    23733, 24476, 24862, 23480, 24181, 24182, 
    24499, 23728, 24937, 24888, 24547, 
    24829, 24828, 24523, 23641, 24834
  ) 
  AND pfv.product_id IN (
    36300, 44278, 47967, 33698, 40928, 44575, 
    36293, 48680, 48150, 44941, 47622, 
    44752, 35705, 47608
  ) 
  AND pfv.lang_code = 'en'

Query time 0.03365

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "variant_id",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "PRIMARY",
          "key_length": "6",
          "used_key_parts": ["feature_id", "product_id"],
          "rows": 238,
          "filtered": 0.027683349,
          "attached_condition": "pfv.feature_id in (23733,24476,24862,23480,24181,24182,24499,23728,24937,24888,24547,24829,24828,24523,23641,24834) and pfv.product_id in (36300,44278,47967,33698,40928,44575,36293,48680,48150,44941,47622,44752,35705,47608) and pfv.lang_code = 'en'",
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "fv",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY", "feature_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "ref": ["dev_db.pfv.variant_id"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "fv.feature_id = pfv.feature_id"
        }
      },
      {
        "table": {
          "table_name": "fvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["dev_db.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "fvd.lang_code = 'en'"
        }
      }
    ]
  }
}