diff --git a/mashumaro/config.py b/mashumaro/config.py
index e2a3df4d..90d658d3 100644
--- a/mashumaro/config.py
+++ b/mashumaro/config.py
@@ -1,15 +1,9 @@
-from typing import Any, Callable, Dict, List, Optional, Type, Union
+from typing import Any, Callable, Dict, List, Literal, Optional, Type, Union
 
-from mashumaro.core.const import PEP_586_COMPATIBLE, Sentinel
+from mashumaro.core.const import Sentinel
 from mashumaro.dialect import Dialect
 from mashumaro.types import Discriminator, SerializationStrategy
 
-if PEP_586_COMPATIBLE:
-    from typing import Literal  # type: ignore
-else:
-    from typing_extensions import Literal  # type: ignore
-
-
 __all__ = [
     "BaseConfig",
     "TO_DICT_ADD_BY_ALIAS_FLAG",
diff --git a/mashumaro/core/const.py b/mashumaro/core/const.py
index 06bf25c0..4353326b 100644
--- a/mashumaro/core/const.py
+++ b/mashumaro/core/const.py
@@ -5,12 +5,10 @@
     "PY_38",
     "PY_39",
     "PY_310",
-    "PY_38_MIN",
     "PY_39_MIN",
     "PY_310_MIN",
     "PY_311_MIN",
     "PEP_585_COMPATIBLE",
-    "PEP_586_COMPATIBLE",
     "Sentinel",
 ]
 
@@ -24,10 +22,8 @@
 PY_311_MIN = PY_311 or PY_312_MIN
 PY_310_MIN = PY_310 or PY_311_MIN
 PY_39_MIN = PY_39 or PY_310_MIN
-PY_38_MIN = PY_38 or PY_39_MIN
 
 PEP_585_COMPATIBLE = PY_39_MIN  # Type Hinting Generics In Standard Collections
-PEP_586_COMPATIBLE = PY_38_MIN  # Literal Types
 
 
 class Sentinel(enum.Enum):
diff --git a/mashumaro/core/meta/helpers.py b/mashumaro/core/meta/helpers.py
index b1ce168e..cb22df7d 100644
--- a/mashumaro/core/meta/helpers.py
+++ b/mashumaro/core/meta/helpers.py
@@ -32,7 +32,6 @@
 from mashumaro.core.const import (
     PEP_585_COMPATIBLE,
     PY_38,
-    PY_38_MIN,
     PY_39,
     PY_39_MIN,
     PY_310_MIN,
@@ -424,10 +423,7 @@ def is_final(typ: Type) -> bool:
 
 
 def is_init_var(typ: Type) -> bool:
-    if PY_38_MIN:
-        return isinstance(typ, dataclasses.InitVar)
-    else:
-        raise NotImplementedError
+    return isinstance(typ, dataclasses.InitVar)
 
 
 def get_class_that_defines_method(
diff --git a/tests/test_meta.py b/tests/test_meta.py
index 6f189a70..fd557126 100644
--- a/tests/test_meta.py
+++ b/tests/test_meta.py
@@ -1,19 +1,14 @@
 import collections
 import collections.abc
 import typing
-from dataclasses import dataclass
+from dataclasses import InitVar, dataclass
 from datetime import datetime
 
 import pytest
 import typing_extensions
 
 from mashumaro import DataClassDictMixin
-from mashumaro.core.const import (
-    PEP_585_COMPATIBLE,
-    PY_38,
-    PY_38_MIN,
-    PY_310_MIN,
-)
+from mashumaro.core.const import PEP_585_COMPATIBLE, PY_38, PY_310_MIN
 from mashumaro.core.meta.code.builder import CodeBuilder
 
 # noinspection PyProtectedMember
@@ -88,10 +83,9 @@ def test_is_generic_unsupported_python(mocker):
         is_generic(int)
 
 
-def test_is_init_var_unsupported_python(mocker):
-    mocker.patch("mashumaro.core.meta.helpers.PY_38_MIN", False)
-    with pytest.raises(NotImplementedError):
-        is_init_var(int)
+def test_is_init_var():
+    assert is_init_var(InitVar[int])
+    assert not is_init_var(int)
 
 
 def test_is_literal_unsupported_python(mocker):
@@ -542,12 +536,8 @@ def test_get_literal_values():
 
 
 def test_type_name_literal():
-    if PY_38_MIN:
-        module = typing
-    else:
-        module = typing_extensions
     assert type_name(
-        getattr(module, "Literal")[
+        getattr(typing, "Literal")[
             1,
             "a",
             b"\x00",
@@ -564,7 +554,7 @@ def test_type_name_literal():
             typing_extensions.Literal[typing_extensions.Literal["b", "c"]],
         ]
     ) == (
-        f"{module.__name__}.Literal[1, 'a', b'\\x00', True, False, None, "
+        f"typing.Literal[1, 'a', b'\\x00', True, False, None, "
         "tests.entities.MyEnum.a, tests.entities.MyStrEnum.a, "
         "tests.entities.MyNativeStrEnum.a, tests.entities.MyIntEnum.a, "
         "tests.entities.MyFlag.a, tests.entities.MyIntFlag.a, 2, 3, 'b', 'c']"