SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f18a263356092e49c1820e54b23c9c9da50817debd00163359b8d56adb2fd656' 
  AND token = 'xEjkHps0tgW0fgykV9gjq3U8YRNqjBrecHA1p2jHwtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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