SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0eb3afe3069ad2edcc8a17aefccb9ddc99dfb72b0f9288b9d082bcfff2bbee1d' 
  AND token = '0aRubtiKV8bjI6kZOlG+fvaHP81Y2BEzuzyWz85eTCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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