SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8595012e5394ccd56a7deed4e689600feff67b5cee4ffd2c48d012d61248d989' 
  AND token = 'e/lz+BgIYOWB3gUPdMZYbhHKyomIJ6YfwBOPuZPe1Tg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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