SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c6d095926fdee8164a92c20c01cd24d1bdc7fa8b6d1e70fc87f7c9bbe68bd1' 
  AND token = 'MVxKgrw9m9agkZwEdw13jr9NRVCzJAZaZLKR1ompZio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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