SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  netting_product_feature_variants AS pfv 
  INNER JOIN netting_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    6830, 6833, 6834, 6835, 6836, 6837, 6838, 
    6839, 6840, 6841, 6842, 6843, 6844, 
    6845, 6846, 6847, 6862, 6861, 6863
  )

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "ALL",
          "possible_keys": ["PRIMARY"],
          "rows": 45,
          "filtered": 42.22222137,
          "attached_condition": "pfv.variant_id in (6830,6833,6834,6835,6836,6837,6838,6839,6840,6841,6842,6843,6844,6845,6846,6847,6862,6861,6863)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["pucuda_cscart.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "pfvd.lang_code = 'en'"
        }
      }
    ]
  }
}