SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf65028c5970f019878880c1ea33350e7f0dffa1554ecf2b31126b8633ae3de' 
  AND token = '5A586XoXLeYwMZFJzakz7sf2GoMhSbXHXFDhY34DoeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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