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 (
    69631, 69630, 69629, 69632, 69639, 69638, 
    69637, 69640, 71862, 71861, 71860, 
    71863, 73943, 73942, 73941, 73944, 
    73939, 73938, 73937, 73936, 73935, 
    73934, 73933, 73940, 73957, 73956, 
    73955, 73954, 73958, 73962, 73961, 
    73960, 73959, 73963, 73972, 73971, 
    73970, 73969, 73973, 73980, 73979, 
    73978, 73981, 74609, 74608, 74607, 
    74610, 74613, 74612, 74611, 74614, 
    79449, 79450, 87216, 80108, 80109, 
    87215, 87214, 71871, 71868, 71870, 
    71869
  )

Query time 0.01594

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": 62,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (69631,69630,69629,69632,69639,69638,69637,69640,71862,71861,71860,71863,73943,73942,73941,73944,73939,73938,73937,73936,73935,73934,73933,73940,73957,73956,73955,73954,73958,73962,73961,73960,73959,73963,73972,73971,73970,73969,73973,73980,73979,73978,73981,74609,74608,74607,74610,74613,74612,74611,74614,79449,79450,87216,80108,80109,87215,87214,71871,71868,71870,71869)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}