SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6efe0027e8b42e5ae31d2319e9d6c08188cf63c31dbddcd30422e00792743570' 
  AND token = '3mvl574PAWGZZPz5fq02jQhDi/m3RCLNAqzvDIoi3XQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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