SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '964ee3d0c40765b18d98b354119bde8cc1103b9f38512ff6aaeedcfc40a53248' 
  AND token = 'Dw6dmOrUJi95Hmq+hvav+vUSbbIXVXZwqc0dAntd0QI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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