SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c65f979186f28ac708307cb19c04e78fdffe2e0ed453d669e420a66b1ec346f' 
  AND token = 'DqAz8IWyP7Tpyaqa05uhA5p9C95wKP8w/U0PmD/5D4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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