SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef93c58fd9dbe9f774a5b1c33e3e090b376f01a45ca1206d69ab070db983146a' 
  AND token = 'qAzSY0DbVVCkVx0iAr2AuUttdHplTfAiM7yHZraPflw=' 
  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"
    }
  }
}