SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0e68fee622ff0919d5b1124be07497647f4acdd7b4a38da458c3c5028dcbf32' 
  AND token = 'BK/TUn4JFpWgHgUAdgO7JZH+mThGgFUry+V9uwW4Wsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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