SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df2f83c0825ba3f8a94e3458ab1b911a178ebe00aec779faf445dda43a603c82' 
  AND token = '3oYRgGC5fCjcFo23exFd16WrBtPfDosyxAks82U7nLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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