SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da02331040bd7e9adf3806eba1e076eb345cdf68afdfc0342e30cf8e6111ffa7' 
  AND token = '7aAUXwguyqyJ90K966+YTz1yHVh/+i2sOJNtOExRdDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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