SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ea34039d3d56136261f1cbfbf75bfb7a71f2b5ad5888616963d429dfa3e567' 
  AND token = 'DNQ1gVdqC9Y48OpU1SasPCx3mBhBuLXAQ+zU7Qw6U+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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