SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1504e644802fc439e4063a4b193c6a9cdfca86ac54aa972a148169e4fd531b61' 
  AND token = 'BNnTdlYqTXnHRzDg3b0OPB2mXTbbHzxaTy1cC8m42n8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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