SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b0c087df40e1b7864f67ee737880abd285a0ca2bf0cb49cbcd3611fe780ea15' 
  AND token = '51VnWTPQMuzNF7xJNmlpVE7Zp8r4wqAYH87ZpPYN9QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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