SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdeaef206f017f947980614c0c4f246bd4a0307b97d04554ee8799029ea90979' 
  AND token = 'lY83J+Te+zsyXXvxWUAKZw+0Fj1g9huxY3buLKy/Cwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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