SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    68198, 68197, 69685, 70033, 70032, 70031, 
    70030, 70034, 70361, 70362, 70360, 
    73468, 73467, 73466, 73465, 73464, 
    73469, 73462, 73461, 73460, 73463, 
    73475, 73474, 75180, 75181, 75689, 
    75688, 78799, 78798, 78797, 78800, 
    80847, 83430, 83439, 83431, 83432, 
    83433, 83434, 83435, 83436, 83437, 
    83438, 84736, 84735, 84734, 84733, 
    84732, 84731, 84744, 84743, 84742, 
    84741, 84739, 84730, 84737, 84738, 
    87172, 87171, 87170, 87173, 87174
  )

Query time 0.02516

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 61,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68198,68197,69685,70033,70032,70031,70030,70034,70361,70362,70360,73468,73467,73466,73465,73464,73469,73462,73461,73460,73463,73475,73474,75180,75181,75689,75688,78799,78798,78797,78800,80847,83430,83439,83431,83432,83433,83434,83435,83436,83437,83438,84736,84735,84734,84733,84732,84731,84744,84743,84742,84741,84739,84730,84737,84738,87172,87171,87170,87173,87174)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "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": "pfvd.lang_code = 'en'"
        }
      }
    ]
  }
}