SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e6a41ff245cee62057b81417e76aacf32f5dfa7e2a0ec57b4e70c4644cad27' 
  AND token = 'wW0o3lDyfjgJfZGhKmN6xoMqo/ADwqKdyOp9AqC0cAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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