SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79825eff81309dea24da19e97b30948934e2acfab58455833fb162e0f4e6d710' 
  AND token = 'YZ1QciogPO8kRwV1ZBabV4cjgdB1RfBWL55NVTrNcHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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