SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2af2c9adee696b9c9170cf7a9712c6de997ff991a7c5f08c5559738172d6697' 
  AND token = 'r+73ePChob5SwmoIz7ZIs+ZrXDTBxPkYwCqK9hGbuMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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