SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '295db6edcfda52319c61d82c4f76fb5aceeeb9e68311cbed47d6baf5281ceb0b' 
  AND token = 'DKmSw24VbcDBRT1C++7BucHkZxHKQFqLIWPYHu5h6wk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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