SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7435260bc36d2578188d012f9523cb27f6aa499c378e0e5ee6a2f1fff5d3789c' 
  AND token = 'Bw7CdQRG+y7ZJY0iqOO+DxpUm5ltTI0UDzf1wChV/i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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