SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '934e390f7569e00f2c359676b4b0e1b84d3f9f9759125e052afa3e1f1f72513f' 
  AND token = 'KTV77c9FUr+vCF/GfDsIX4Yw3FssCqmWvOnPZg9jMD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}