SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '499f3b2fe9d9313ab432f6f68c37069d023c529323dcd8ab05a95d202e39ff53' 
  AND token = '/jKUmGjygWDH3PNEQBaaAKkJwlCcr/8BhoMksKGJq+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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