SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '90b64fb15f80ad3e08cdd8793893df2114921b43573f60717a7c87c7db18212c' 
  AND token = 'n/7/oJ5rvtahU5HPQqJPAbrPTEbsaFWCs3wbGSwkNJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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