SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e850ee179b8d75a21f0d11f79db8d7a40b3a873fb3af6060bad76688654f6f07' 
  AND token = 'CrwdAHwB73uKNgCnUh11GNJey5KzeSmmlC/QQ3HpsBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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