SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c323c8d6ee37e05493a2d55cc5f225968e1db3a022ab9e1519bf0dda28c68b23' 
  AND token = 'IafxgTPM7J1/secbQTbpBuyqHetoFVQu1RTDSiKxgbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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