SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9335b31f203b7fb6df35eda8b11275778fe658a654a326c3fdac2a6f965b28d7' 
  AND token = 'RI0tlMnj4SG6mmkCr67D7aR1HLd3OpEnT7/PlyBuivc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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