SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2832ce51f2d8f49a963064030a59945c1b28f7335e8e47421ff93721a68c4ea2' 
  AND token = 'mh3LAwcP8VppwkPugUdF6KkAQmqCUHIqC9dAg2vZhS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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