SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dd56355b62c3ea7c58b725bc3212acee6fc7b7c72402b864170b73edc0a62ee' 
  AND token = 'WLq/+/pruMSestNvMTuqD6iNYf6Yl+j+TFzg3Eg9keA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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