SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '235004b9cb948d25a214c842028b4036f4d35f96058da99c35181c15cb11766e' 
  AND token = 'BdRY52X4EI41DiMHZj4C0ZdhgHrI3pNTuepRBrM3re4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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