SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c3b31ce1b4d6c3de120c098a80eab8b63965349d34b9d14972b8cd0ae5b35f06' 
  AND token = 'NKhu/Np+DXwjFWHgh+JD9ZTDvS7Jls1EFlcZ5l9hTY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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