SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5305ca1ad0bd83bf87146c56cf47e882ebe4c0e753e4084792f726051ac754a5' 
  AND token = 'ZfrbVyQ/JvQPPJNgOUbuq3WMSVS+sn/rZHB2LclQHMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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