SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '242096180980582b693731a8696154d96b6660d4815783482f8a7973f34f49b6' 
  AND token = '0Hz3w4xHR0BD7yccxoPY6VD3qp/lcfx6vdIQEAZKgAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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