SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fba3ba124a3911c3934c5c660015de8af5e6b4360f4dea7c3035af6234495118' 
  AND token = 'S8NCUP3QZaMuWBqeNaJInFwCC9F8UAWdcuZX5yge0mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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