SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e998aa135d693151cd5c5d898059244105afc128863b1d68260ff2f844fdb6bb' 
  AND token = '9B3QNjXh28p2KgX9MwqGbhKXcGRUt/y7GWfwM1KHti4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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