SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8030c9fbae192bdf9e31e67b8d503135ca724f8968e0baf6645a6de6867bdf36' 
  AND token = 'AFj3hvXh0T4vBst18IPpDSG1QCtZdYsYmcw+PHCjkDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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