SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec3ea8d1addb7f4471a9095641a492eb09ce6766726bfacaab43b0999e299d3d' 
  AND token = 'ucJ1KFnQGSne83ynldMhjKahwIyR5FnJZKApMB9SuNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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