SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd53bee6a2b49d2faa5864ddc540dfae35d5c0f2adb42fd6e46408659cceba921' 
  AND token = '8P7OYThvGfAHb+OHj9iqI/gOP1y6I+CfC8QRz3ySkc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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