SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac5121b20c98b7b241da0036ad3c4d99f06d5a219bcb8e279c8d3574cbd38b81' 
  AND token = 'djrkCkGkuSWw5clkmTQRF2KaPbTfufISbMqBv0/ynuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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