SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe8ea52f609a845d22710fd8fdfcd1047f80edb16d786c5a2bb85f79d4b6e99' 
  AND token = 'XtKSlObFSjHlxrPjFlEj7pNAnCpMWbVDO8Reods2xcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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