SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffcb0ee4ee8a402d0ed883fd313d2caf540c41871c26466ce7a11c28902ea6c6' 
  AND token = '1mZwY91AnuIJGIVMCvGDKca9hfdVCw37SeLusLBXrkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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