SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '233c2f1c324691a87c06e1098c1f816eb5d068c9e814e098806b3785460f7223' 
  AND token = 'H6LG0rdZLETgGM9WBrFtFidX4cixfLwHTVlAt6USMJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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