SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfe2fc9dabcf31aa4a78eeccad83d26fb465cbb4694aeddb243a7e369b27276b' 
  AND token = 'xIv8nwEmBCTW1DWnXXagEBJ5BjK+MShMkn55plnRB5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}