SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b596736c7430c77b064eec621bc3f402806ad4d55f91a15db7efa520938a5d8a' 
  AND token = 'zVu131dDH1ksBkXrJRREiKGOu39MZ8V/CLujXfZ8YUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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