SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b29f6bf56290b159dfeb6e54130525e01117fb288be32d13ce6af16163ba4781' 
  AND token = 'JEvmGDoHQGawmOhEl/X35Z48MR/9lCs7yJIdQTPGoZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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