SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16b1bd90ccbb66d8e360896328184f282b4f83e216c0ea5c255aa91ddf536390' 
  AND token = 'Hr7OAg0Kv5iDLzfUvFk4elRQhKgWyUUjwlZmeFD8YoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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