SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eb94c284fd19442b59d0446ae024f7cbdaa21e8329c1db8d2508ccafc3002a6' 
  AND token = 'nOuFgYNyEmLXzJWwlHXZuP5bhe7JJio+4bQiBOlFyqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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