SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76fd086ddebcbf22b0650a23e33fc4c232c55ea6faed347a2e21a2113d5aebc9' 
  AND token = 'bGueex0tGkOhoVJnlbFwFSbZSgd6ObV4RrQ02Wllgew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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