SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89c3e7599944efab5391da6878fc207012110256daa0eb73b074180074b9ed80' 
  AND token = 'WkVg0KrkqSMzvqKLbDg8rKu4vyAmOBIffckVJAUzOGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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