SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '239094fc24f4d3bd5cb892922d617ffbd76be6e88f9642e782a9dfa75bfe1833' 
  AND token = 'fHVOIiXOYcxOR/OR2hW7VwOzMBkUwcXRZgFjXfoSSIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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