SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f700803d9e24111fce48d00cd4daad60bd25ddbfd634ab5144d64175b2cac91' 
  AND token = '3I6vty7fW+FQRu9TcbjNupjKyTzjvUXMDaZM9pYG0XE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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