SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9bf1231996bf2ada87044d8bfc27f161ed44ccbff6b2532fd89b895355d650' 
  AND token = '8gdW+9uHJBjd0iX9MOsAzUJo+jxkJrwxUYG51AvH0XA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}