SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06b78d6caff93aacf18d8dce2359268af384d8f15bf67831746d08aeec95909f' 
  AND token = '2lqV+ZfMJ5i6FtDdyiZD/8hmzmAF8e01Txw7KvsaBNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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