SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '623ff21cf2b2cd2f431b0d58778c41ba8534033c2fe883c08fae8f47fa223423' 
  AND token = '2KDE+ZCFFjceFkEji4p3jmZ/WH39hZ+iDLjRbjz429o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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