SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57ea4063ee17a61736a2787c133c8856603cbb7d577c1361401fe2c8c79435b8' 
  AND token = 'DF1bFxIyOgil5zwI+aOdyTdc130g600HALUxgTfuNmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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