SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9c74db0b122d1731993385b85259b25649c0ab1c427b5c1a38496ec195685110' 
  AND token = '1z+V0OENiYSgPVSQIzBjrhpPRjRMEm9NfciFUfUYdv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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