SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2caaf60324964b8771b27c9e04c96a9a605c3500fe49f438b513c1113b8df62b' 
  AND token = 'YZ1OEpM7I0v2ZLQkxTB+Ht6lDZh5YOBqPx+1uEjiu48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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