SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c439afe7a00ecb9134be9bf825a455ec687bb8171c07f03b7ea2ef2a4298f7db' 
  AND token = 'KE/9QLIvnc6HIqFBZzjWOiSoPQLleGnq7U0HQ/fVK64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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