SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cc8cd95bb10521f1d3110c4526de5e43854979b960117b0178d80253b0c6851' 
  AND token = 'ViUYRi4NKZIv68OnDeEmc5FR9cxhUXKteaRv9W5GS9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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