SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '520fc2bbeeb171cb8d184e1a681a436c587815effb717b5fe9dbb18c228f3fad' 
  AND token = 'pphCkDJR8M8JZ6ydxdYyrHa7TbSmt53n8EUFv+9OXnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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