SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03daf5350512f6bf2fb8241a14d48f95971e9207de2a5803c77c442937a798a7' 
  AND token = '8CAiNoaawJyi6vG5HSvC0llZ4qC5UanCAtdNiydfWDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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