SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98ef641d1f6c6c0cec75ff8387bc40bffb0011c7642371e244793dde5948eea2' 
  AND token = '/p4hC3VSj2gLzd3vanLIFB99uoAYNQLMKBVvjHK/YQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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