SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a75801aa06f15d7c6b4d9798eb163fb7eaa40ac0bf3807b89561d9e3efdf02' 
  AND token = 'IrfU5vG3YapJKKaVEf/5zZWwCjSmzRpmfZhQuU8gj9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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