SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56f4f3c6c9c2ad704c218df5aa9a875225b05737144d6be24d437822cd4553db' 
  AND token = '0dAM6pj9pQCwTa8ywTiKOL2PJQtgne28TU8M9Z67p3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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