SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cab17f5b33e4249702311ddf173a0cb03ff00eaa622001eeace2bf75134d5c63' 
  AND token = '5e10zWVGN5AtsHfjmHmBxyUYrH8z0QYWVIqJYXgVlig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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