SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c35131d46818285163bcf818c686f5eaa6d71594064b40670eb3fa8cece5b29' 
  AND token = 'aUX16Xdh0c4dZOdqWivx4IPaVtYXnTo8KHBBj0Es/7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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