SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6244e758feef475922b4c920177e9f1e32c04e652018e7d974ba86bb138cfbab' 
  AND token = 'UVef9h1RZ4mFI3wCxDoZwHwJksz4NwyFPyMgzBWJVGI=' 
  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"
    }
  }
}