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 (
    23794, 23767, 24862, 23590, 22058, 23793, 
    24798, 23328, 23329, 23334, 23332, 
    23413, 23414, 22060, 24181, 24182, 
    24779, 23607, 23215, 23312, 22067, 
    23137, 24594
  ) 
  AND pfv.product_id IN (
    37413, 36765, 47967, 35486, 828, 37420, 
    32435, 32404, 32327, 32324, 33198, 
    826, 40928, 47280, 35655, 31735, 32307, 
    816, 29816, 45361
  ) 
  AND pfv.lang_code = 'en'

Query time 0.01304

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": "product_id",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rowid_filter": {
            "range": {
              "key": "fl",
              "used_key_parts": ["feature_id", "lang_code"]
            },
            "rows": 164,
            "selectivity_pct": 0.103758067
          },
          "rows": 119,
          "filtered": 0.103758067,
          "index_condition": "pfv.product_id in (37413,36765,47967,35486,828,37420,32435,32404,32327,32324,33198,826,40928,47280,35655,31735,32307,816,29816,45361)",
          "attached_condition": "pfv.feature_id in (23794,23767,24862,23590,22058,23793,24798,23328,23329,23334,23332,23413,23414,22060,24181,24182,24779,23607,23215,23312,22067,23137,24594) and pfv.lang_code = 'en'"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}