SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cb1b49364ab2c517b4153536959b4a5e98a6f00499cbe482e3b6ffc059c8d39b' 
  AND token = 'LmMYbYL0UKjALh8uzUzL6qH0dmpZpavFo4l+OxiOLsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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