SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dcf588f922970d577418037f93c66aa064e684f091861f4fbd8f1fd201cbe6e' 
  AND token = 'bARVI85QENziTfGxH6kxRdBpGmzk88GNG6MFyd728TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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