SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9904bd5c3fcf081e1f3890959eb688bb90d8890ec6d704c00bf060854929ad6' 
  AND token = 'Uqz2iTizs+fI7loL7OZT8qCjkeo3E8DrVDIbSvIGMks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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