SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc114b42ae030eee89c0a4fec2034c77c1e1d92736eaad8ffce85ed4f5fc345' 
  AND token = '8h3xjFrY1ptvVlqSfKI0JpZNbE0ThvB5FNQpyyghDuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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