SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '901deed843967db60cf82400cbade6ed40f017799519dc1ba877117775e9c691' 
  AND token = 'x3FidPfe660mH7xBFfgzTAjX4ElP4emPZbOWAmQR+xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}