SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cbf060e9511e0978a0cd1e9143bc383a597af826cf1fa81b9c63e9c8b20ba94' 
  AND token = 'oNcDwJ0REQbRAoTzNQVkhKaLyiqCC/xVU+MhPmXWwG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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