SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6308836329e9cde02388b245c9237eb15ff4aee60b3d8334ce761ef287002643' 
  AND token = 'qZRUtn6mU5z2vVPUY4UrCDKKVn5x1ZVynGXMVnPUZ/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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