SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23591ddda5c9d262c4451da28bf8b69330d74cbbadfbf807844085694864e37' 
  AND token = 'LkV1KF3MiMG3/joScGY8pZs8SMA58JAH9nYYFIDnyA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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