SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2223bb3c2cadfc7044fedd19865334ffc29cdb2b904f5ceb987e6cbf29e20709' 
  AND token = 'TfLStVB6BcioRUggzpObk6i2l+wBVS1moax3PkIuGpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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