SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d28a12b96298e33f210be489ddd88ba0c7b7b9e0a890be5408ec5372e72872' 
  AND token = '008jGpIWwhuvXf9OqniL64pCsQ6IQrkkbdOfclKoumY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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