SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ced53c829e64158cf21bace74e5dd83483ada47a927afdb5e29d38143b5c94ab' 
  AND token = 'qSE5DxIri5WkpDKvlDKUwSLfhfyrXwfESAfqnuKVTtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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