SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '428a5c862607094ee51b2db02904c9315423268aac347da364175091eb9e38cc' 
  AND token = 'IExlgb2lRkOhBhKicQRvGlt592JAqU6LKQkfNxtONeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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