SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '551fdb3bd294bd2f3888959d8ce414aaef59815e4102500c5acb825f67594c1f' 
  AND token = 'tHYXlv/7nnyUflVn21ezyYY3qqvKNvtq3pghQgz7rJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}