SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ff43769ad2a5a97765265825014a326ca21c9623294495a194af32b01675d7' 
  AND token = 'IUT7xlURKw7D3wRRqoxwxVEBFQdYxxpeNzP1/AWEpdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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