SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b4a2f1a2839d5f89a34951f15bf8567cc7d28739c242cb72074e9cd2c531a98' 
  AND token = 'lFXGevGjVbTwR39OU/IbKviW/kdYRaLguyAkPBtvR8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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