SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ab3eaf1764d7c21a60e7ce55c1d33bebf7e3686e788794bcb3b43b6d064936' 
  AND token = '6GkjfP+FRI52Zy+bJjXg41aVZw95KQQWigHmGhbFD9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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