SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d397128185b25e4f2bf788a9d3cbe71184516596f9fd46b6d85aeb642349a77' 
  AND token = 'ZnQVnpZVsRa7ykreZ9+BftKVYlH/rxC38+NBKsM5Bro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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