SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90382b8519a542099778866a704fb6e2b14e05dce5db89308f4adb1045f3e07b' 
  AND token = 'a+jGTlOsUuhzBg7RGM0GQMz2i/V6B5lzZYuVacSXvMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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