SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53bbe0d306d6140678570818ec41e8da5b80dd85fc6067116014c6540d01def6' 
  AND token = 'qjd7o5rXmshUkuzrYqFbIWtlbXtYFWSxaJfLJEgk72Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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