SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c3c4c41b401eec66f7a08c6ca58f46edc877965957ac348f510710bb96bb94c' 
  AND token = '2oKcVA1gfZDOoQ/PFmouTK9LepZ/qHRRiUuTFzacubo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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