SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '177d16e15c24f060bf006865614ca5610d424f8376ad0e7c15d70a0c300d859f' 
  AND token = 'L6MFmoWppYqR0rLFJRcOkM5p0OuSM5TPli54nYyL+sI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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