SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '852e90db221cb8cced447f108c6adb193c529069a6670a7ff7452c1d816033a9' 
  AND token = 'x3FlxTpsseztfq0ooFRxXTN882MQGXvundL54uINHwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}