SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59c61da820813739495d12b56a7b80718e76eaa826191099e3b8a3a04809906b' 
  AND token = 'UpWhsVF8eBEZz0ClKLA57ecEEEz+ak4UNiKYsQ7O5RU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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