SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6767d6edbb6ae786c76ab06ad006c80b5ffa1455453d572aca788d68869e910' 
  AND token = 'nFNFsjdfeG7rdFu5UGZm64KJTCAiOCXI3WWJfiL/9M8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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