SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00b7398e3af91684f7a19bf8d632d50d554664d91814140fd7fc866612a147fa' 
  AND token = 'zqe1expuB9kU86ZnvgSrSrZP2wzsKCJoMy3US/50UCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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