SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd863d13ce697a98e17a8c5069ab98400d52e05234dc93ee140cf75e97a98ef91' 
  AND token = 'h815sTOxOyVdSU76rHKn0XLhG5+vKLQmy4ittqWkjvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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