SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5d41f6c051bf921b0ce67f263021a255a75606c2a477d58da08511a7780aff0' 
  AND token = 'NRfzrZUwTl5YLtEAXfOhIhaFUhJMexfgoY7ZF1roDcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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