SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f58da04da18f73d867569bfc78ecad35e6bc2512b6ad7ab824a540dc7f792a5c' 
  AND token = 'qy/n5VnATW6BV9JW4iDs/PegDGR8Mwgj+NgM3u3YN9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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