SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e28417b64b7392e985c93bbbccefdde100683f84ab0570e36a9f3c535f5abe2a' 
  AND token = 'aUiIONkd8SdzUNHgbi9XweKDO5lapyWIwNAAa4SdIlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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