SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e151179a1725c54ea57ca1cfe50a525e0e4438ba67640ae574c430b4fa414bb' 
  AND token = 'ShsIBuK26ye0QEKZIlyjZO758nSSYpu5hR8fsw+6RQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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